Mould for the production of metal ingots

ABSTRACT

A mould for the production of metal ingots, having a casing, a shield and an inductor congruent in shape with an elongated loop, with the inductor made up of electrically insulated other parts with each part connected to two power supply sources producing in the opposite parts thereof electric currents which are in opposite phase.

United States Patent 91 Kozheurov et al.

MOULD FOR THE PRODUCTION OF METAL INGOTS Inventors: Vsevolod Rodionovich Kozheurov, O.

Koshevogo, l3 kv. 8; Leonid Georgievich Berezin, ulitsa Sverdlova, 44, kv. 9; Georgy Samuilovich Safarov, ulitsa Dzerzhinskogo, 5/8, kv. 12; Petr Lavrentievich Bulgakov, ulitsa Zhukovskogo 3, kv. 2-, all of Belaya Kalitva Rostovskoi obl'asti, U.S.S.R.

Filed: Nov. 3, 1971 Appl. No.: 195,215

u.s. c1 164/250, 164/49, 164/273, 219/75 1111. C1 B2211 27/02 Field of Search 164/48, 82, 89, 283, 164/49, 51, 251, 281, 50, 52, 250, 252, 27 I 219/75 /2 I l 1 FT:

[56] References Cited UNITED STATES PATENTS 3,467,166 9/1969 Getselev et al. 164/48 X 3,605,865 9/1971 Getselev 164/250 2,686,864 8/1954 Wroughton et al.. 2l9/7.5 3,688,834 9/1972 Wagstaff et al 164/283 Primary Examiner-J. Spencer Overholser 'Assistant Examiner-John E. Roethel Attorney-Holman & Stern [57] ABSTRACT A mould for the production of metal ingots, having a casing, a shield and an inductor congruent in shape with an elongated loop, with the inductor made up of electrically insulated other parts with each part connected to two power supply sources producing in the opposite parts thereof electric currents which are in opposite phase.

5 Claims, 5 Drawing Figures MOULD FOR THE PRODUCTION OF METAL INGOTS BACKGROUND OF THE INVENTION The present invention relates to moulds for manufacturing metal ingots having shapes which are preferably wide and flat.

Known in the art are plants for the continuous and/or semi-continuous production of the ingots, all of the plants having a common element a shaping means or a mould whose walls, being in contact with liquid metal, determine the shape of the ingot being cast.

The walls of the shaping means are also used to execute primary heat extraction from the metal. This leads to the formation of a hard skin which comes off the walls of the shaping means and on being heated up produces shrinkage cracks and headings and only then is exposed to coolant action (secondary heat removal).

Between the walls of the shaping means and the ingot, being cast (its liquid portion inclusively), arise friction forces and it is to reduce these forces that lubricants are employed. The lattertend however to detract from ideal conditions of production.

Further heating of the ingot after the primary heat removal results in secondary liquidation of low-melting ingot constituents. I

Macrostructure defects lead to unnecessary expenditures on ingot heat treatment, to a reduction in production ratesduring metal working and to inferior mechanical properties of the ingots.

Thus orthodox moulds produce defects both on the ingot surface and in its macrostructure (coarse-grained zones over an ingot section).

Utilization of extra labor on machining can remove surface defects but this is associated with the formation of chips whose remelting tends to increase both the non-recoverable losses of metal and production expenditures.

Known in the art is apparatus comprising, as a major element, a mould for producing metal ingots, which is furnished with a ring-shaped inductor for performing molten metal into a cylindrical ingot fastened in a casing, having a cavity, an ingot base plate and double walls which form a passage for a coolant. A mould wall, facing the ingot and fitted with a longitudinal slot, serves for carrying a shield attached to it with a clearance through which the coolant is fed to the ingot. The foregoing apparatus facilitates the production of ingots of adequate quality and is more advantageous when compared to the plants incorporating a mould wherein the shape of the ingots are mechanically formed with the aid of the walls of the mold. However when the above apparatus is utilized for the production of a flat ingot of a rectangular cross-section, 300 X 1,260 mm., the voltage across the indicator has to be maintained within a 90-100 V. range which results in a loud high frequency hissing proving detrimental to the health of attending personnel.

In addition, as has been established experimentally, dissimilar sized planes of the flat ingot will require different intensities of cooling for which purpose the above apparatus is not suitable at all.

Since the coolant in the known plant is fed in a turbulent flow, it adversely affects the quality of the ingot surface (which becomes covered with folds and wrinkles} and is liable to increase coolant consumption per se.

LII

Additionally in the specified apparatus it is not possible to provide the coolant outlet slot having the same dimensions throughout the perimeter of the ingot, which tends to aggravate the aforesaid surface defects.

Since no provision is made to compensate thermal expansion of the shield under operating conditions, the latter is distorted and has a small operating life.

SUMMARY OF THE INVENTION The main object of the present invention is to develop a mould for the production of wide flat ingots, operating at a voltage, less than 40 V. which is safe for operating personnel.

Another object of this invention is to develop an inductor which would not produce high frequency noise so as is adversely affect both the mould attentants and those occupied with other jobs in the vicinity.

It is also an object of the invention to devise a mould which would ensure the fabrication of a flat ingot featuring better quality, a smooth polished surface and a more uniform structure due to better coolant supply.

In addition an object of the present invention-is to provide the possibility of using the aforesaid mould in conventional casting machines in current use and of reducing both the coolant and power costs.

These and other objects are achieved by developing a mould for the production of metal ingots, comprising an inductor intended for transforming liquid metal into the ingot, secured in a casing which has an ingot cavity, a base plate and double walls forming a passage for a coolant, with the casing carrying and attached to it, a clearance shield, located on a side wall facing the ingot and having a longitudinal slot, with the clearance designed for feeding the coolant to the ingot, in which mould, according to this invention, the inductor is in the form of an elongated loop and is built up of elements electrically insulated from each other with each of them coupled to two power supply sources, producing in the opposite elements electric currents in opposite phase, and with the mould casing and the shield being congruent in shape with the inductor.

The mould, supplied with the inductor, shield and casing according to the above requirements, assures safe maintenance and enhanced quality of production in the manufacture of flat ingots.

It would be expedient to divide the coolant passage, provided in the casing, with cross walls into a series of chambers, located both in longitudinal and transverse members of the casing made in the form of the stretched out loop, and to fit each chamber with a sleeve to prime it with the coolant.

This will allow the supply of an adequate amount of cooling agent to those sides of the ingots which differ in width.

It is also desirable to provide the mould casing with a damping screen positioning it along each chamber opposite to the sleeve.

In this manner a turbulent flow of cooling agent, fed from the sleeve to the chamber, will be converted into a laminar flow which will be supplied through the slot onto the ingot.

It is also possible to fit longitudinal elements of the shield with oblong holes for casing gluts and to provide expansion gaps between the transverse elements of the shields thus allowing for thermal expansion of the shield.

This will prevent the shield from being distorted when the mould is in operation.

It would be sound practice to apply to the casing wall facing the ingot, in a coolant feeding zone, a layer of selfhardening mixture, congruent in shape with a shield external surface and forming an outlet coolant slot.

This will permit the coolant flow, fed to the ingot, to be kept uniform in width.

BRIEF DESCRIPTION OF THE DRAWINGS To make the nature of the present invention more fully apparent an exemplary embodiment thereof is described with reference to the appended drawings, in which:

FIG. 1 shows a fragmentary cut-away plan view of a mould;

FIG. 2 section II-II of FIG. 1;

FIG. 3 depicts an inductor made up of two parts;

FIG. 4 section IV-IV of FIG. 3;

FIG. 5 section V-V of FIG. 3.

A mould for the production of ingots has a casing 1 (FIGS. 1 and 2) which can be manufactured from a non-conducting material (textolite) and consist of one or several integrally constructed plates. Casing 1 constitutes a container for a cooling agent on which are attached other elements of the mould. It is made in the form of an elongated loop with cavity 2 fora flat ingot.

External wall 3 and internal wall 4 of casing 1 form annular coolant conduit 5, with external wall 3 fitted with sleeves 6 for feeding the said cooling water into conduits 5, whereas wall 4 facing the ingot is provided with circular slot 7 through which the coolant is delivered from conduit 5 in the ingot direction. Annular conduit 5 provided in casing 1 is subdivided by vertical cross walls 8 into chambers 9 with either chamber having its sleeve 6 for feeding the coolant.

This makes it possible to control both the coolant consumption and pressure required for heat extraction during the ingot forming process which is of prime importance in producing ingots of alloys prone to'cracking. Each chamber 9 of casing 1 contains damping screen 10 located opposite the sleeve 6. This screen is present so as to convert a turbulent coolant flow into a laminar one flowing via slot 7 over wall 4 which is act ing as a baffle.

Attached on cover 11 of casing 1 on the wall 4 side is a shield 12. The latter is made from a non-magnetic material, such as stainless steel. To prevent thermal deformation, longitudinal portions of flanges of shield 12 are fitted with oblong holes for gluts 13 provided on cover 11 of easing 1, whereas between cross members of shield 12 and casing 1 there are extension gaps 14 to allow for the thermal expansion of shield 12.

Casing 1 is separated from shield 12 by rubber or paralon lining 15 whose function is to keep the coolant from leaking from the flanges of shield 12.

Formed between shield 12 and a projection 16 of interval wall 4, is a coolant stilling chamber 17. It has no lateral partitions and the coolant leaves it passing through outlet slot 18 in a continuous laminar flow. The slot 18 is made in width by coating projection 16 with a layer 19 of self-hardening mixture whose surface is parallel to that of shield 12; The size of slot 18 can also be adjusted with the aid of adjusting screws 20. Owing to this, not only coolant consumption can be controlled but evaporative cooling can be utilized.

For holding the ingot on a movable element of a conventional casting machine use is made of base plate 21 allowed to displace vertically. On the upper portion of base plate 21 there is recess 22. It is needed to facilitate initiation of the casting operation, to increase the rate and to preclude the occurence of bottom cracks on the ingot. As regards a shape of base plate 21, it shall comply with that of cavity 2 of mould casing l and with a section of the ingot being performed. The size of base plate 21 is chosen so that it can fit with a clearance into ingot cavity 2, restricted by shield 12, casing 1 and inductor 23.

Inductor 23 (FIGS. 4 and 5) is the most significant shape-determining element of the mould. It is fastened under projection 16 (FIG. 2) of casing 1 by means of retractable straps 24 which can be stripped to allow' easy inspection and replacement of inductor 23. The

latter is made from tubular water-cooled currentcarrying copper buses 25 (FIGS. 4 and 5).

Inductor 23 has the form of an elongated loop and is built up of electrically insulated parts 26 and 27 with either part connected to two power supply sources, generating in the said opposite parts electric currents being in counter phase. By coupling each part of inductor 23 to two power sources (transformers, not shown in the drawing) it is possible to obtain a safe voltage across inductor 23 in casting ingots up to 1.5 m. wide and to eliminate noise which is detrimental to the health of the attending personnel. r The casting ofwide flat ingots is accomplished as follows. I

A mould is set up on the upper part of a conventional casting machine.

On feeding a coolant via sleeve 6 into chambers 9 of conduit 5 its pressure and consumption are adjusted with the aid of known valves (not shown in the drawing) arranged in front of sleeves 6 and with adjusting screws 20 displacing shield 12 in a vertical direction relative to casing 1.

Next base plate 21 is introduced into shield 12 so that the coolant, fed through clearance (slot) 18 formed by shield 12 and projection 16 of casing 1, would hit only its lateral face.

Following that moisture is removed (for example, blown off with compressed air) from recess 22in base plate 21.

For cooling inductor 23 the coolant is fed into an interior of buses 25. Then the voltage, produced by different power sources, is applied to inductor 23 to generate in its opposed members electric currents being in opposite phase.

An electromagnetic field generated by inductor 23 is adjusted by shield 12 not to interfere with the shaping of the ingot on the side it is built up.

Mounted above recess 22 is base plate 21 is a commonly known metal distributor (not shown in the drawing).

The metal is fed via the distributor into recess 22 in base plate 21, whereafter a known metal proportioning device (not shown in the drawing) serves to maintain a pre-set level of the metal in relation to inductor 23.

As soon as the specified metal level is achieved, base plate 21 is lowered relative to shield 12 ensuring thereby withdrawal of the ingot from the mould with the ingot being continuously built up with liquid metal.

Various adjustments are allowable in the course of the casting process, thus consumption and pressure of the cooling agent, the voltage value across inductor 23, the rate of travel of base plate 21 rate and metal level relative to inductor 23 can be corrected.

To terminate the process ingot displacement is ceased, the ingot is held until crystallization is completed, whereupon inductor 23 is de-energized and coolant supply cut-off. The mould, together with the power supply sources mounted on a carriage (not shown in the drawing), is rolled off to withdraw the ingot from the casting machine.

Side removal of the ingot is also feasible. If that is the case, the fact that both the power supply sources and the mould are installed on a common carriage is very convenient in service.

The present invention has been subjected to a trail operation at an industrial plant where it has been used for the serial production of conventional castings on orthodox casting machines.

The trials have provide high efficiency of casting flat rectangular and hexagonal ingots as well as those with chamfered edges into the said electromagnetic mould. They have also displayed serviceability of the mould.

1. A mould for the production of ingots comprising: a casing with a cavity for an ingot and double walls forming a conduit for a coolant, with the wall facing the ingot fitted with a lengthwise coolant outlet slot; a base plate closing the ingot cavity in the said mould casing; a shield fastened on the said ingot facing wall of the casing with a clearance to supply the coolant to the ingot; an inductor secured in the said casing for forming liquid metal into the ingot, said inductor having the shape of an elongated loop formed of a pair of opposed parts which are electrically insulated from each other and are each connected to two power supply sources, producing in the opposite parts electric currents being in counter phase; with the said mould casing and shield congruent in shape with the said inductor.

2. A mould of claim 1 in which a coolant conduit made in a casing is subdivided by cross walls into a Thus in casting a flat ingot, 1,460 mm wide and 300 number of chambers located in longitudinal and transverse elements of the casing, having the form of an elongated loop, with each chamber fitted with a sleeve to supply into it the coolant.

3. A mould, of claim 2, in which along each chamber and opposite to a sleeve is set up a damping screen.

4. A mould of claim 1, in which lengthwise portions of a shield are furnished with oblong holes for casing gluts and cross members of the shield and the casing are separated by expansion gaps to make for thermal expansion of the shield.

5. A mould of claim 4, in which a casing wall facing the ingot, in the coolantoutlet zone, is coated with a layer of selfhardening mixture congruent in shape with an external surface of the shield forming an outlet coolant slot.

i l i 

1. A mould for the production of ingots comprising: a casing with a cavity for an ingot and double walls forming a conduit for a coolant, with the wall facing the ingot fitted with a lengthwise coolant outlet slot; a base plate closing the ingot cavity in the said mould casing; a shield fastened on the said ingot facing wall of the casing with a clearance to supply the coolant to the ingot; an inductor secured in the said casing for forming liquid metal into the ingot, said inductor having the shape of an elongated loop formed of a pair of opposed parts which are electrically insulated from each other and are each connected to two power supply sources, producing in the opposite parts electric currents being in counter phase; with the said mould casing and shield congruent in shape with the said inductor.
 2. A mould of claim 1 in which a coolant conduit made in a casing is subdivided by cross walls into a number of chambers located in longitudinal and transverse elements of the casing, having the form of an elongated loop, with each chamber fitted with a sleeve to supply into it the coolant.
 3. A mould, of claim 2, in which along each chamber and opposite to a sleeve is set up a damping screen.
 4. A mould of claim 1, in which lengthwise portions of a shield are furnished with oblong holes for casing gluts and cross members of the shield and the casing are separated by expansion gaps to make for thermal expansion of the shield.
 5. A mould of claim 4, in which a casing wall facing the ingot, in the coolant outlet zone, is coated with a layer of selfhardening mixture congruent in shape with an external surface of the shield forming an outlet coolant slot. 